This invention relates generally to diagnostic imaging methods and apparatus, and more particularly, to methods and apparatus that provide for the prediction of a bolus's arrival in a region of interest.
Contrast Enhanced Angiography studies are an important clinical tool that provide a way to monitor the arrival of contrast agents for CT Angiographic (CTA) applications. When the mean signal intensity over a user defined region of interest (ROI) reaches a pre-defined threshold, the operator can initiate the CT scan to capture arterial phase images. It is desirable to image the vasculature of interest while the contrast bolus resides in the arterial system, prior to parenchymal and venous enhancement (so-called “venous contamination”). Therefore, the primary challenge in CTA imaging is to time the CT (Computed Tomography) scan to coincide with the peak contrast bolus in the arterial system.
This tool is available today in the General Electric Company's CT scanner and it is called SmartPrep. Since its introduction well over a decade ago, SmartPrep has become an indispensable tool to customers, and is used many times daily at sites throughout the world. A SmartPrep protocol consist of two scan phases; one called “Monitor phase”, where the user observes the progress of the contrast in the ROI and “Scan phase” when the actual scan of the ROI occurs according to protocol selected.
The current SmartPrep feature does a good job of monitoring the contrast dynamics over a small ROI in some applications, but the time to transition from the monitor mode to the scan mode may be too long and variable for some clinical situations. Therefore, it would be desirable to shorten the transition time from the monitor mode or phase to the scan mode or phase. Imaging the carotid arteries, for example, requires a very short monitor-to-scan delay, on the order of a second or two, to minimize venous contamination. Furthermore, increases in scanner performance in terms of slice coverage and rotation speed demand shorter latencies and more precise timing control. This is particularly true in the case of the LightSpeed 64 and 32 Scanners commercially available from the General Electric Healthcare business of The General Electric Company. In addition, the time to move the table from the monitor location to the beginning of the scan location adds to the overall latency.